What did you do when the sun went down? If you’re reading this, chances are you switched on a light. But for the 1.3 billion people around the world who lack access to electricity, darkness is a reality. There is no electric light for children to do their homework by, no power to run refrigerators that keep perishables or needed medicine cold, no power for cooking stoves or microwaves. What light they have mostly comes from the same sources that humans have relied on forever–firewood, charcoal or dung–and the resulting smoke turns into indoor pollution that contributes to more than 3.5 million deaths a year. “For us, life does not stop after dark,” says Michael Elliott, president and CEO of the development nonprofit ONE. “For 550 million people in sub-Saharan Africa and many more than that around the rest of the world, it does.”

That lack of electricity is called energy poverty, and it’s a development challenge that hasn’t gotten the attention it deserves. It’s easy to see why. Extreme poverty, global hunger, HIV/AIDS and malaria are all immediate threats to human life. Not having somewhere to plug in a cell phone, by contrast, might seem like an inconvenience at worst. But energy poverty is connected to a host of deeper ills: 90% of the children in sub-Saharan Africa go to primary schools that lack electricity, which means no fans or air conditioners in the equatorial heat, no computers, no lights for evening classes. Economic growth is stunted as a result–60% of African businesses cite access to reliable power as a binding constraint on their operations. Energy poverty is even a political issue. In Pakistan, which has just half the electrical-generation capacity of the state of Virginia, frustration over an antiquated grid helped get President Asif Ali Zardari kicked out of office this year.

The good news is that the issue is slowly receiving more notice. This summer, President Barack Obama announced his Power Africa initiative, which promises more than $7 billion over the next five years to bring electricity access to 20 million new households in countries like Ethiopia and Ghana. Development groups like ONE have begun making energy poverty a priority, weaving it into long-standing health and economic programs. “A light where currently there is darkness. The energy needed to lift people out of poverty,” Obama told South African students in June. “That’s what opportunity looks like.”

The Price of Progress
But the challenge is enormous. While some 1.7 billion people have acquired access to electricity globally since 1990, the rate of electrification has been slower than the rate of population growth in the most energy-poor countries. Just to get all of sub-Saharan Africa–a region that generates about as much electricity as Spain–up to levels that comparatively well-off South Africa enjoys would require 330 gigawatts of new capacity. (Power Africa should account for about 10 gigawatts.) The World Bank estimates that it would take $1 trillion a year in global investment to eliminate energy poverty by the year 2030–more than twice what is being spent now. And even that level of investment would guarantee the poorest of the poor only enough electricity to run a floor fan, a mobile phone and two compact fluorescent lights for five hours a day.

The reality is that banishing energy poverty won’t be easy or cheap, and it may come with an environmental cost. Much of Africa can and will be supplied with renewable energy sources–especially rural areas beyond the reach of any grid, where solar fits perfectly. But the fastest population growth is happening in the developing world’s exploding urban areas, which will eventually need the same reliable, grid-delivered electricity that developed cities enjoy. Some of that electricity will be generated by fossil fuels, including carbon-heavy coal. The result may well be an increase in greenhouse gases, but given that the average Ethiopian emits less than 1% of the carbon that the average American does, Africans should hardly feel climate guilt. For those who live in darkness, electricity by nearly any means will be worth the price.